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In semiconductor wafer manufacturing, wafer substrates are often transported in wafer carriers. The industry has been migrating to the use of 300 mm wafers. When fully loaded, a 300 mm wafer carrier holds 25 wafers and weighs more than eight kilograms. Frequent manipulation of a payload of this size and weight may lead to repetitive strain injuries for operators in wafer fabrication facilities. Person-guided vehicles are being developed to assist operators in transporting and delivering these large carriers to their destinations. Person-guided vehicles, however, are heavy when loaded and can be difficult to manipulate, often requiring the operator to bend at the waist.
The invention provides a person-guided vehicle (PGV) for assisting an operator in the transportation and delivery of 300 mm wafer carriers to various destinations in the factory.
More particularly, the PGV comprises a cart comprising a frame, the frame having a load port side configured to align with the load port. The cart also includes wheels and at least one handle positioned to be grasped by an operator to push or pull the cart. A carrier support assembly is mounted to the frame. The carrier support assembly comprises a cradle configured to support the carrier, a lifting mechanism operative to raise and lower the cradle vertically, and a horizontal slide mechanism operative to move the cradle horizontally to and from a position outboard of the cart. A damping system is coupled to the cart and operative to dampen vibrations of the carrier in the carrier support assembly. The side of the cart opposite the load port side is left free of structural members to allow an operator to manipulate the cart to dock it at the load port using the large muscles of the leg and eliminating or minimizing bending at the waist.
The damping system comprises a damping device, such as a shock absorber, that may be coupled to the lifting mechanism, the cradle, or the legs of the cart. In another embodiment, the cart may include a subframe mounted within the frame and the damping system may comprise a damping device coupled between the subframe and the frame. The damping system also includes bumpers on the horizontal slide mechanism and on legs of the cart. The damping system also includes a suspension system coupled to the wheels of the cart.
The cradle comprises a pair of arms configured to support the carrier thereon. The lifting mechanism comprises a vertically oriented track, and the cradle is mounted for vertical travel along the track. The horizontal slide mechanism comprises a horizontally oriented track, and the lifting mechanism is mounted for horizontal travel along the track. The side of the cart opposite the load port side that is free of structural members allows operator access to the carrier support assembly.
The PGV also includes a docking mechanism configured to couple with a latch mechanism at the load port. The docking mechanism may comprise a hook mechanism configured to hook to a latch pin at the load port. A handle is coupled to the hook mechanism to actuate the hook mechanism. The hook mechanism may be retractable within the periphery of the cart.
The PGV can be configured to include a plurality of carrier support assemblies, either horizontally or vertically. Preferably, two carrier support assemblies are provided.